      Special value nil / HTTP response 404 is returned in case of any I/O error."
     [file-name content-type]
     (let [file (new java.io.File "www" file-name)]
-        (println-and-flush "Returning file " (.getAbsolutePath file))
+        (log/debug "Returning file " (.getAbsolutePath file))
         (if (.exists file)
             (-> (http-response/response file)
                 (http-response/content-type content-type))
-            (println-and-flush "return-file(): can not access file: " (.getName file)))))
+            (log/debug "return-file(): can not access file: " (.getName file)))))
 
 (defn handler
     "Handler that is called by Ring for all requests received from user(s)."
     [request]
-    (println-and-flush "request URI: " (request :uri))
+    (log/info "request URI: " (request :uri))
     (let [uri (request :uri)]
         (condp = uri
             "/favicon.ico"       (return-file "favicon.ico" "image/x-icon")

                (.replaceAll desc "\n" "<br />")))
        (catch Exception e
            ; print error message in case of any DB-related exception
            (println-and-flush "read-description(): error accessing database '" (:subname (second product)) "'!")
            (println-and-flush e)
            (.printStackTrace e)
            (println "***********" package)
            nil)))  ; special value that will be handled later

(defn try-to-read-description

                (store-ccs-description (clojure.string/lower-case trimmed-package-name) new-description)
                (generate-response trimmed-package-name new-description output-format new-user-name old-user-name)
                (catch Exception e
                    (log/error e "Error writing into database 'ccs_descriptions.db':")
                    (generate-error-response trimmed-package-name old-user-name (str "Can not write into database file 'ccs_descriptions.db': " e))))
            (generate-response trimmed-package-name new-description output-format new-user-name old-user-name))))

